Magneto-resistance effect element, magnetic memory and magnetic head

ABSTRACT

The magneto-resistance effect element includes: a first ferromagnetic layer serving as a magnetization fixed layer; a magnetization free layer including a second ferromagnetic layer provided on one side of the first ferromagnetic layer, a third ferromagnetic layer which is formed on an opposite side of the second ferromagnetic layer from the first ferromagnetic layer and has a film face having an area larger than that of the second ferromagnetic layer and whose magnetization direction is changeable by an external magnetic field, and an intermediate layer which is provided between the second ferromagnetic layer and the third ferromagnetic layer and which transmits a change of magnetization direction of the third ferromagnetic layer to the second ferromagnetic layer; and a tunnel barrier layer provided between the first ferromagnetic layer and the second ferromagnetic layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based upon and claims the benefit of priorityfrom prior Japanese Patent Application No. 2002-339934, filed on Nov.22, 2002 in Japan, the entire contents of which are incorporated hereinby reference.

FIELD OF THE INVENTION

[0002] The present invention relates to a magneto-resistance effectelement, a magnetic memory and a magnetic head.

RELATED ART

[0003] A magneto-resistance effect element having magnetic films is usedfor a magnetic head, a magnetic sensor and so forth, and it has beenproposed to be used for a solid magnetic memory. In particular, there isan increasing interest in a magnetic random access memory (hereinafter,referred to as “MRAM (Magnetic Random Access Memory)), which utilizesthe magneto-resistance effect of ferromagnetic material, as a nextgeneration solid non-volatile memory capable of carrying out a rapidreading/writing and an operation with large capacity and low powerconsumption.

[0004] In recent years, a ferromagnetic tunnel junction element or theso-called “tunneling magneto-resistance element (TMR element)” has beenproposed as a magneto-resistance effect element utilizing a tunnelcurrent and having a sandwiching structure where one dielectric isinserted between two ferromagnetic metal layers, and a current is causedto flow perpendicular to a film face to utilize a tunneling current. Inthe tunneling magneto-resistance element, since a magneto-resistancechange ratio (MR ratio) has reached 20% or more, a possibility of theMRAM to public application is increasing.

[0005] The tunneling magneto-resistance element can be realized bydeposing a thin Al (aluminum) layer with a thickness of 0.6 nm to 2.0 nmon a ferromagnetic layer, and thereafter, exposing the surface of the Allayer to oxygen glow discharge or oxygen gas to form a tunnel barrierlayer comprising Al₂O₃.

[0006] Further, a ferromagnetic single tunnel junction having astructure where a magnetization direction of one of ferromagnetic layersconstituting the ferromagnetic single tunnel junction element is fixedby an anti-ferromagnetic layer has been proposed.

[0007] Furthermore, a tunneling magneto-resistance element wheremagnetic particles have been dispersed in a dielectric and aferromagnetic dual tunnel junction element have been proposed.

[0008] In view of the fact that a magneto-resistance change ratio in arange of 20% to 50% have been also achieved in these tunnelingmagneto-resistance elements and the fact that reduction inmagneto-resistance change ratio can be suppressed even if a voltagevalue to be applied to a tunneling magneto-resistance element isincreased in order to obtain a desired output voltage value, there is apossibility of the TMR element to application to the MRAM.

[0009] When the TMR element is used in the MRAM, one of twoferromagnetic layers sandwiching a tunnel barrier layer, i.e., amagnetization fixed layer whose magnetization direction is fixed so asnot to change is defined as a magnetization reference layer, and theother thereof, i.e., a magnetization free layer whose magnetizationdirection is constituted to be easily reversed is defined as a storagelayer. Information or data can be stored by causing a parallel statewhere the magnetization directions of the reference layer and thestorage layer are parallel and an anti-parallel state where they areanti-parallel to correspond to “0” and “1” of binary information.

[0010] A writing operation of record information is performed byinverting the magnetization direction in the storage layer by an inducedmagnetic field generated by causing current to flow in a writing wireprovided in the vicinity of the TMR element. Further, a readingoperation of record information is conducted by detecting a resistancechange amount due to a TMR effect.

[0011] For the purpose of fixing the magnetization direction in thereference layer, such a method that an anti-ferromagnetic layer isprovided so as to come in contact with a ferromagnetic layer so thatoccurrence of inverting magnetization is made hard by the exchangecoupling force is employed, and such a structure is called a spin valvetype structure. In this structure, the magnetization direction of thereference layer is determined by annealing while applying a magneticfield (magnetization fixing annealing). On the other hand, the storagelayer is formed such that a magnetization easy axis of the storage layerand the magnetization direction of the reference layer are madeapproximately equal to each other by applying a magnetic anisotropy.

[0012] A magnetic recording element using the ferromagnetic singletunnel junction or the ferromagnetic dual tunnel junction has such acharacteristic that writing/reading time can be conducted at a highspeed such as 10 nanoseconds or less, even if it is non-volatile, and ithas a potential such that the number of rewritings is 10¹⁵ or more. Inparticular, as described above, in the magnetic recording element usingthe ferromagnetic dual tunnel junction element, even if a voltage valueto be applied to the tunneling magneto-resistance element is increasedin order to obtain a desired output voltage value, reduction inmagneto-resistance change rate can be suppressed so that a large outputvoltage can be obtained. Thus, a preferable characteristic can bedeveloped as the magnetic recording element.

[0013] However, regarding a cell size of the memory, when anarchitecture where a cell is constituted by one transistor and one TMRelement is used, there occurs such a problem that the cell can not bereduced down to the size of a DRAM (Dynamic Random Access Memory) of asemiconductor device or smaller.

[0014] In order to solve this problem, a diode type architecture where aTMR element and a diode are connected in series between a bit line and aword line and a simple matrix type architecture where a cell having aTMR element is disposed between a bit line and a word line have beenproposed.

[0015] However, in the both cases, since reversal is conducted with acurrent magnetic field due to current pulses at a writing time into astorage layer, power consumption is large. Further, since an allowablecurrent density in a wire when a mass storage is to be achieved islimited, the mass storage can not be achieved. Furthermore, unless anabsolute value of a current flow is 1 mA or less, an area of a driverfor allowing a current to flow becomes large. There occurs such aproblem that the memory becomes large in chip size, as compared withanother non-volatile solid magnetic memory, for example, a ferroelectricrandom access memory using a ferrodielectric material capacitor, a flushmemory or the like, so that a competitive power of the memory is lost.

[0016] In order to solve the above problem, magnetic storage deviceswhere a thin film comprising magnetic material with a high magneticpermeability is provided about a writing wire have been proposed (referto U.S. Pat. No. 5,659,499; U.S. Pat. No. 5,956,267; and U.S. Pat. No.5,940,319). According to these magnetic storage devices, since amagnetic film with a high magnetic permeability is provided about awire, a current value required for information writing in a magneticrecording layer can be reduced efficiently.

[0017] However, even if these magnetic storage devices are used, it hasbeen much difficult to suppress the writing current value to 1 mA orless.

[0018] Further, storage layers (magnetization free layer) of aferromagnetic tunneling junction which have been conventionally proposedare usually determined according to their volumes defined at a time ofjunction separation, and there occurs a problem about thermal stabilitywhen the design rule becomes 0.25 μm or less. In order to solve theabove problems, it has been proposed to form a three-layered film or amulti-layered film where a storage layer has been joined in ananti-ferromagnetic coupling (for example, refer to U.S. Pat. No.5,953,248).

[0019] However, when a structure of the multi-layered film disclosed inU.S. Pat. No. 5,953,248 is employed, such a problem arises that amulti-hysteresis occurs and an MR change rate lowers.

SUMMARY OF THE INVENTION

[0020] The present invention has been made in view of theabove-described circumstances and an object thereof is to provide amagneto-resistance effect element whose power consumption is reduced andthermal stability is excellent, a magnetic memory using themagneto-resistance effect element and a magnetic head using the same.

[0021] A magneto-resistance effect element according to a first aspectof the present invention includes: a first ferromagnetic layer servingas a magnetization fixed layer; a magnetization free layer including asecond ferromagnetic layer provided on one side of the firstferromagnetic layer, a third ferromagnetic layer which is formed on anopposite side of the second ferromagnetic layer from the firstferromagnetic layer and has a film face having an area larger than thatof the second ferromagnetic layer and whose magnetization direction ischangeable by an external magnetic field, and an intermediate layerwhich is provided between the second ferromagnetic layer and the thirdferromagnetic layer and which transmits a change of magnetizationdirection of the third ferromagnetic layer to the second ferromagneticlayer; and a tunnel barrier layer provided between the firstferromagnetic layer and the second ferromagnetic layer.

[0022] A magneto-resistance effect element according to a second aspectof the present invention includes: a first ferromagnetic layer servingas a magnetization fixed layer; a magnetization free layer which isprovided on one side of the first ferromagnetic layer, the magnetizationfree layer having a T-shape in a section perpendicular to a film facethereof taken along a magnetization easy axis of the magnetization freelayer; and a tunnel barrier layer provided between the firstferromagnetic layer and the magnetization free layer.

[0023] A magnetic memory according to a third aspect of the presentinvention includes a first wiring, a second wiring crossing the firstwiring and a magneto-resistance effect element according to the firstaspect, which is provided in a crossing region of the first and secondwirings, wherein the second and third ferromagnetic layers of themagneto-resistance effect element constitute a storage layer whosemagnetization direction is changeable according to a magnetic fieldgenerated by causing a current to flow in at least one wiring of thefirst and second wirings, and the third ferromagnetic layer is providedadjacent to the one wiring generating the magnetic field.

[0024] A magnetic memory according a fourth aspect of the presentinvention includes a first wiring, a second wiring crossing the firstwiring and a magneto-resistance effect element according to the secondaspect, which is provided in a crossing region of the first and secondwirings, wherein the magnetization free layer of the magneto-resistanceeffect element constitutes a storage layer whose magnetization directionis changeable according to a magnetic field generated by causing acurrent to flow in at least one wiring of the first and second wirings,and the magnetization free layer is provided adjacent to the one wiringgenerating the magnetic field.

[0025] A magnetic head according to a fifth aspect of the presentinvention includes a magneto-resistance effect element according to thefirst aspect as a magnetic reproducing element.

[0026] A magnetic head according to a sixth aspect of the presentinvention includes a magneto-resistance effect element according to thesecond aspect as a magnetic reproducing element.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027]FIG. 1 is a sectional view showing a structure of amagneto-resistance effect element according to a first embodiment of thepresent invention;

[0028]FIG. 2A is a perspective view showing a case where themagneto-resistance effect element according to the first embodiment hasbeen used in a magnetic memory, and FIG. 2B is a perspective viewshowing an intermediate layer in the magneto-resistance effect elementaccording to the first embodiment;

[0029]FIG. 3 is a sectional view showing a structure of a firstmodification according to the first embodiment of the magneto-resistanceeffect element;

[0030]FIG. 4 is a sectional view showing a structure of a secondmodification according to the first embodiment of the magneto-resistanceeffect element;

[0031]FIG. 5 is a sectional view showing a structure of a thirdmodification according to the first embodiment of the magneto-resistanceeffect element;

[0032]FIG. 6 is a sectional view showing a structure of a fourthmodification according to the first embodiment of the magneto-resistanceeffect element;

[0033]FIG. 7 is a sectional view showing a structure of a fifthmodification according to the first embodiment of the magneto-resistanceeffect element;

[0034]FIG. 8 is a sectional view showing a structure of a sixthmodification according to the first embodiment of the magneto-resistanceeffect element;

[0035]FIG. 9 is a sectional view showing a structure of a seventhmodification according to the first embodiment of the magneto-resistanceeffect element;

[0036]FIG. 10 is a sectional view showing a structure of an eighthmodification according to the first embodiment of the magneto-resistanceeffect element;

[0037]FIGS. 11A to 11F are plan views of magnetic layers of writingwirings of the magneto-resistance effect element according to the firstembodiment;

[0038] FIGS. 12(a) to 12(h) are plan views of intermediate layers of themagneto-resistance effect element according to the first embodiment;

[0039]FIG. 13 is a diagram showing asteroid curves;

[0040]FIGS. 14A and 14B are views showing a structure of a magneticmemory according to a second embodiment of the present invention;

[0041]FIGS. 15A and 15B are views showing a structure of a magneticmemory according to a third embodiment of the present invention;

[0042]FIGS. 16A and 16B are views showing a structure of a magneticmemory according to a fourth embodiment of the present invention;

[0043]FIGS. 17A to 17C are views showing a structure of a magneticmemory according to a fifth embodiment of the present invention;

[0044]FIGS. 18A to 18C are views showing a structure of a magneticmemory according to a sixth embodiment of the present invention;

[0045]FIGS. 19A and 19B are views showing a structure of a magneticmemory according to a seventh embodiment of the present invention;

[0046]FIGS. 20A and 20B are views showing a structure of a magneticmemory according to an eighth embodiment of the present invention;

[0047]FIGS. 21A and 21B are views showing a structure of a magneticmemory according to a ninth embodiment of the present invention;

[0048]FIGS. 22A and 22B are views showing a structure of a magneticmemory according to a tenth embodiment of the present invention;

[0049]FIGS. 23A and 23B are views showing a structure of a magneticmemory according to an eleventh embodiment of the present invention;

[0050]FIGS. 24A and 24B are views showing a structure of a magneticmemory according to a twelfth embodiment of the present invention;

[0051]FIG. 25 is a view showing a structure of a magnetic memoryaccording to a thirteenth embodiment of the present invention;

[0052]FIG. 26 is a view showing a structure of a magnetic memoryaccording to a fourteenth embodiment of the present invention;

[0053]FIG. 27 is a view showing a structure of a magnetic memoryaccording to a fifteenth embodiment of the present invention;

[0054]FIG. 28 is a view showing a structure of a magnetic memoryaccording to a sixteenth embodiment of the present invention;

[0055]FIGS. 29A and 29B are views showing a structure of a magneticmemory according to a seventeenth embodiment of the present invention;

[0056]FIGS. 30A and 30B are views showing a structure of a magneticmemory according to an eighteenth embodiment of the present invention;

[0057]FIGS. 31A to 31F are sectional views showing manufacturing stepsof a magneto-resistance effect element according to an nineteenthembodiment of the present invention;

[0058]FIGS. 32A to 32E are sectional views showing manufacturing stepsof the magneto-resistance effect element according to the nineteenthembodiment of the present invention;

[0059]FIGS. 33A to 33F are sectional views showing manufacturing stepsof a magneto-resistance effect element according to an twentiethembodiment of the present invention;

[0060]FIGS. 34A to 34C are sectional views showing manufacturing stepsof the magneto-resistance effect element according to the twentiethembodiment of the present invention;

[0061]FIGS. 35A and 35B are sectional views showing a structure of a TMRelement having a T-shaped magnetization free layer which is used in themagnetic memories according to the seventh and the eighth embodiments;

[0062]FIG. 36 is a sectional view showing a structure of a modificationof the magneto-resistance effect element according to the firstembodiment;

[0063]FIG. 37 is a perspective view showing a schematic structure of aprincipal part of a magnetic recording and reproducing apparatus; and

[0064]FIG. 38 is an enlarged perspective view of a magnetic headassembly extending from an actuator arm as viewed from a disc side.

EMBODIMENTS OF THE INVENTION

[0065] Embodiments of the present invention will be explained below withreference to the drawings.

First Embodiment

[0066] A structure of a magneto-resistance effect element according to afirst embodiment of the present invention will be shown in FIG. 1. Amagneto-resistance effect element 2 of this embodiment is aferromagnetic tunneling junction element (hereinafter, also referred toas “TMR element”) used in a memory cell of a magnetic memory andcomprises a magnetization free layer 3, a tunnel barrier layer 4 and amagnetization fixed layer 5 which serves as a reference layer. Themagnetization free layer 3 comprises a ferromagnetic layer 3 a servingas a storage layer provided on a side of the tunnel barrier layer 4opposed to the magnetization fixed layer 5, an intermediate layer 3 band a magnetic layer 3 c magnetically exchange coupled via theintermediate layer 3 b. The magnetic layer 3 c is provided adjacent to awriting wiring 10 in which a writing current flows when writing data orinformation is written in the TMR element 2.

[0067] In this embodiment, such a structure is employed that theferromagnetic layer 3 a, the intermediate layer 3 b, the tunnel barrierlayer 4 and the magnetization fixed layer 5 have substantially the sameplane configuration and their aspect ratios (=length in an longitudinalaxis/length of a short axis) are 2 or less. Further, the magnetic layer3 c adjacent to the writing wiring 10 is constituted so as to be largerin area of a film face than the ferromagnetic layer 3 a.

[0068] That is, the ferromagnetic layer 3 a, the intermediate layer 3 band the magnetic layer 3 c eventually form a T-shaped magnetization freelayer 3 as viewed in section. In the T-shaped magnetization free layer3, the direction of magnetic moment is mainly supported by the magneticlayer 3 c provided adjacent to the writing wiring 10. That is, magneticanisotropy is mainly applied to the magnetic layer 3 c. On the contrary,magnetic anisotropies of the ferromagnetic layer 3 a and theintermediate layer 3 b can be controlled so as to be small. This controlcan easily be attained by controlling respective plane shape of theirlayers 3 a and 3 b, as described later. The ferromagnetic layer 3 a, theintermediate layer 3 b and the magnetic layer 3 c are coupled by amagnetic exchange coupling.

[0069] In the T-shaped magnetization free layer thus constituted, when acurrent pulse is caused to flow in the writing wiring 10 and a currentmagnetic field is applied, because the distance between the writingwiring 10 and the magnetic layer 3 c provided adjacent to the writingwiring 10 is very short, the current magnetic field acts on the magneticlayer 3 c effectively so that a magnetization of the magnetic layer 3 ccan be inverted easily with a low current. When a magnetizationdirection of the magnetic layer 3 c provided adjacent to the writingwiring 10 is inverted, the ferromagnetic layer 3 a and the intermediatelayer 3 b whose magnetic anisotropies are set to be smaller than that inthe magnetic layer 3 c are inverted simultaneously due to the magneticexchange coupling. That is, the intermediate layer 3 b transfersinversion of the magnetization direction of the magnetic layer 3 c tothe magnetic layer 3 a.

[0070] Further, since the volume of the T-shaped magnetization freelayer 3 is much larger than the conventional magnetization free layercomprising only the ferromagnetic layer 3 a, an excellent thermalstability can be achieved and a stable spin magnetic moment can bemaintained even in a design rule of 0.1 μm or less. Thereby, practicaluse of a MRAM with 1 Gbit (Gigabit) or more can be made possible.

[0071] In this embodiment, since the ferromagnetic layer 3 a and theintermediate layer 3 b each have a low aspect ratio, a large capacitycan be achieved.

[0072] Incidentally, the intermediate layer 3 b may be a single-layeredmagnetic layer, and it may be multi-layered film where a magnetic layer3 b 1 and a non-magnetic layer 3 b 2 have been disposed alternately, asshown in FIGS. 2A and 2B. In case of the multi-layered film wheremagnetic layers and non-magnetic layers have been disposed alternately,it is preferable that anti-ferromagnetic exchange coupling orferromagnetic exchange coupling between adjacent magnetic layers via anon-magnetic layer exists. Incidentally, in FIG. 2B, the intermediatelayer 3 b shows an anti-ferromagnetic exchange coupling. A ferromagnetictunneling junction type magneto-resistance effect element 2 providedwith the magnetization free layer 3 comprising the intermediate layer 3b with such a structure, the ferromagnetic layer 3 a and the magneticlayer 3 c, the tunnel barrier layer 4 and the magnetization fixed layer5 is generally provided at each crossing point between an upper wiring(writing wiring) 10 and a lower wiring 20, as shown in FIG. 2A.

[0073] Further, the intermediate layer 3 b may be a non-magnetic metallayer and it may have the same size as the magnetic layer 3 c, as shownin FIG. 36. Even in this case, an anti-ferromagnetic exchange couplingor a ferromagnetic exchange coupling exits in the ferromagnetic layer 3a and the magnetic layer 3.

[0074] Next, first to eighth modifications of the magneto-resistanceeffect element according to the first embodiment will be explained withreference to FIGS. 3 to 10. FIG. 3 shows a structure of amagneto-resistance effect element according to the first modification. Amagneto-resistance effect element 2 according to the first modificationhas a structure that the magnetic layer 3 c provided adjacent to thewriting wiring 10 also extends on a side portion of the writing wiring10 in the ferromagnetic tunneling junction element. Incidentally, in thefirst modification, an anti-ferromagnetic layer 6 which fixesmagnetization direction of a magnetization fixed layer 5 comprisingferromagnetic material is provided on a face of the magnetization fixedlayer 5 which is positioned on the opposite side of the tunnel barrierlayer 4. However, in the first embodiment shown in FIG. 1, ananti-ferromagnetic layer 6 is provided and it is omitted. Thoughmagnetization direction of the magnetization fixed layer 5 can be fixedby another method, it is unnecessary to provide an anti-ferromagneticlayer 6, but it is preferable that magnetization direction of themagnetization fixed layer 5 is fixed by the anti-ferromagnetic layer 6.Incidentally, in each of modifications of the first embodiment describedbelow, an anti-ferromagnetic layer 6 is also provided. In themagneto-resistance effect element according to the first modification,since the volume of the magnetization free layer 3 is increased ascompared with that in the first embodiment, a thermal stability in themodification is improved.

[0075]FIG. 4 shows a structure of a magneto-resistance effect elementaccording to the second modification. A magneto-resistance effectelement 2 of the second modification has a structure that anintermediate layer 3 b is formed in a multi-layer film where magneticlayers and non-magnetic layers have been stacked alternatively in theferromagnetic tunnel junction element shown in FIG. 1.

[0076] In the multi-layered film, an anti-ferromagnetic exchangecoupling or a ferromagnetic exchange coupling exists between adjacentmagnetic layers via a non-magnetic layer.

[0077] Incidentally, a non-magnetic layer may exist between the magneticlayer 3 c adjacent to the writing wiring and a magnetic layer closest tothe magnetic layer 3 c of the magnetic layers constituting theintermediate layer 3 b, and the magnetic layer 3 c and the magneticlayer closest to the magnetic layer 3 c may come in direct contact witheach other. Further, a non-magnetic layer may exist between theferromagnetic layer 3 a serving as a storage layer and a magnetic layerclosest to the ferromagnetic layer 3 a of the magnetic layersconstituting the intermediate layer 3 b, and the ferromagnetic layer 3 aand the magnetic layer closest to the ferromagnetic layer 3 a may comein direct contact with each other.

[0078] In the magneto-resistance effect element 2 according to thesecond modification, since the magnetization free layer 3 is increasedin volume as compared with that in the first embodiment, an increasedthermal stability can be achieved. Further, since the intermediate layer3 b has the multi-layered film structure where magnetic layers andnon-magnetic layers have been stacked alternatively, it is made possibleto prevent multi-stage hysteresis from occurring, an MR change ratio (MRratio) can be made high and a high output can be achieved.

[0079]FIG. 5 shows a structure of a magneto-resistance effect elementaccording to a third modification. A magneto-resistance effect element 2according to the third modification has a structure that a magneticlayer 3 c also extends on a side portion of the writing wiring 10 in thesecond modification shown in FIG. 4. In the magneto-resistance effectelement according to the third modification, since the volume of themagnetization free layer 3 is increased as compared with that in thesecond modification, a thermal stability in third modification isimproved. Further, since the intermediate layer 3 b has themulti-layered film structure that the magnetic layer and thenon-magnetic layer have been stacked alternatively, a MR change ratiobecomes high and a high output can be achieved.

[0080]FIG. 6 shows a structure of a magneto-resistance effect elementaccording to a fourth modification. A magneto-resistance effect element2 according to the fourth modification has a structure that a magneticsubstance covering film (yoke) 8 is provided on the opposite side of thewriting wire 10 from the magnetic layer 3 c in the third modificationshown in FIG. 5. When the yoke 8 is further provided on the writingwiring 10, it is made possible to further reduce a writing current, anda spin inversion (an inversion of a magnetization direction) can be madepossible by a writing current with 0.2 mA or less. Incidentally, when nocurrent flows in the writing wiring 10, there does not occur a magneticinteraction between the yoke 8 and the magnetization free layer 3 of themagneto-resistance effect element 2. Since the volume of the magneticfree layer 3 is larger than that of the conventional one, a thermalstability is increased. Further, since the intermediate layer 3 b hasthe multi-layered film structure where the magnetic layer and thenon-magnetic layer have been stacked alternatively, a MR ratio can bemade high and a high output can be achieved.

[0081]FIG. 7 shows a structure of a magneto-resistance effect elementaccording to a fifth modification. A magneto-resistance effect element 2according to the fifth modification has a structure that a magneticlayer 3 c adjacent to the writing wiring 10 has a stacked structurecomprising a magnetic layer 3 c 1, a non-magnetic layer 3 c 2 and amagnetic layer 3 c 3 in the second modification shown in FIG. 4. Whenthe multi-layered film of the stacked structure is employed in themagnetic layer 3 c in this manner, the volume of the magnetization freelayer 3 becomes larger than that of the second modification, so thatfurther improvement of a thermal stability can be achieved. Furthermore,since the intermediate layer 3 b has the multi-layered film structurewhere the magnetic layer and the non-magnetic layer have been stackedalternatively, a MR ratio can be made high and a high output can beachieved.

[0082]FIG. 8 shows a structure of a magneto-resistance effect elementaccording to a sixth modification. A magneto-resistance effect element 2according to the sixth modification has a structure that a yoke 8 isfurther provided on the opposite side of the writing wiring 10 from themagnetic layer 3 c in the fifth modification shown in FIG. 7. This sixthmodification can achieve a further thermal stability like the fifthmodification. Further, since the yoke 8 is provided in thismodification, a writing current can be further reduced and a spininversion can be conducted with a writing current of 0.2 mA or less.Incidentally, when no current flows in the writing wiring 10, there isnot a magnetic interaction between the yoke 8 and the magnetization freelayer 3 of the magneto-resistance effect element 2. In addition, sincethe intermediate layer 3 b has the multi-layered film structure that themagnetic layer and the non-magnetic layer have been stackedalternatively, a MR ratio becomes high and a high output can beachieved.

[0083]FIG. 9 shows a structure of a magneto-resistance effect elementaccording to a seventh modification. A magneto-resistance effect element2 according to the seventh modification has the same structure as themagneto-resistance effect element 2 according to the third modificationshown in FIG. 5, and the seventh modification has a structure that themagneto-resistance effect element 2 has been provided on the writingwiring 10. The seventh modification can achieve improvement in thermalstability like the third modification. Further, since the intermediatelayer 3 b has the multi-layered film structure that the magnetic layerand the non-magnetic layer have been stacked alternatively, a MR ratiobecomes high and a high output can be achieved.

[0084]FIG. 10 shows a structure of a magneto-resistance effect elementaccording to an eighth modification. A magneto-resistance effect element2 according to the eighth modification has the same structure as themagneto-resistance effect element of the sixth modification shown inFIG. 8, and the eighth modification has a structure that themagneto-resistance effect element 2 has been provided on the writingwiring 10. The eighth modification can achieve improvement in thermalstability like the sixth modification. Further, since the intermediatelayer 3 b has the multi-layered film structure that the magnetic layerand the non-magnetic layer have been stacked alternatively, a MR ratiobecomes high and a high output can be achieved. In addition, since theyoke 8 is provided in this modification, a writing current can befurther reduced and a magnetization direction can be inverted with awriting current of 0.2 mA or less. Incidentally, when no current flowsin the writing wiring 10, there is not a magnetic interaction betweenthe yoke 8 and the magnetization free layer 3 of the magneto-resistanceeffect element 2.

[0085] Next, the plane figure of the magnetic layer 3 c which isincluded in the magnetization free layer 3 constituting themagneto-resistance effect element according to the first embodiment andis provided adjacent to the writing wiring 10 will be explained withreference to FIGS. 11A to 11F. Various plane shapes of the magneticlayer 3 c are shown in FIGS. 11A to 11F. FIG. 11A shows an oval shape,FIG. 11B shows a Rugby ball shape, FIG. 11C shows a shape obtained bycutting corners from a rectangular shape, FIG. 11D shows a rectangularshape, FIG. 11E shows an octagonal shape, and FIG. 11F shows a crossshape. It is preferable that each of plane figures of the magneticlayers 3 c has an aspect ratio (=longitudinal axis/short axis) of 1 ormore except for plane figures of the octagonal shape shown in FIG. 11Eand the cross shape shown in FIG. 11F. That is, the magnetic layer isformed such that the length L1 thereof in a direction substantiallyperpendicular to a current direction in which a current flows in thewriting wiring 10 is longer than the current direction. Incidentally,the current direction corresponds to the short axis and a directionsubstantially perpendicular to the current direction corresponds to thelongitudinal axis. As described later, when current pulses are appliedto two wirings substantially perpendicular to each other to conduct aspin inversion, a stable magnetic anisotropy can be achieved byemploying these curves, and curves of asteroids are improved. In case ofthe aspect ratio of 1:1, when the plane figure of the magnetic layer 3 cis formed in an octagonal shape or a cross shape, the curve of theasteroid becomes good. Moreover, the form of an asteroid will becomegood when the direction of the magnetization easy axis is leaned 30degrees to 60 degrees to the direction of a longitudinal axis of thewiring. The fact that a curve of asteroid is good means that an asteroidis positioned so as to be closer to coordinate axes than other asteroidcurves g2 and g3, as an asteroid g1 shown in FIG. 13, so that a value ofa switching magnetic field at a time of spin inversion is small while avalue of the switching magnetic field is large except for the time ofspin inversion. By attaining such an asteroid curve, cell selection ismade easy.

[0086] FIGS. 12(a) to 12H show plane figures of the intermediate layer 3b. FIGS. 12(a) to 12(d) show plane figures of the intermediate layer 3 bhaving a ratio of the length W in a current direction in which a currentflows in the writing wiring 10 and the length L in a directionperpendicular to the current direction of 1:1, and FIGS. 12(e) to 12(h)show plane figures thereof having cases that L is longer than W.Incidentally, such a structure is employed that L becomes shorter thanthe length L1 of the magnetic layer 3 c in a longitudinal axis.

[0087] In each of the above cases, such a structure is employed that anarea of a film face of the magnetic layer 3 c provided adjacent to thewriting wiring 10 is larger than the areas of the film faces of theintermediate layer 3 b and the ferromagnetic layer 3 a constituting thetunnel junction type magneto-resistance effect element.

[0088] Further, it is preferable that the aspect ratio of the film faceof the magnetization free layer is 1 or more but 2 or less even ineither section parallel with the film face.

[0089] In these magneto-resistance effect elements 2, as ferromagneticmaterial which can be used in the magnetization fixed layer 5, themagnetic layer 3 a serving as the storage layer and the intermediatelayer 3 b, for example, Fe (iron), Co (cobalt), Ni (nickel) or alloythereof, oxides having a large polarizability in spin, such asmagnetite, CrO₂, RXMnO_(3-y) (here, R represents rare earth metal, and Xrepresents one of Ca (calcium), Ba (barium), Sr (strontium)), orHeusler's alloy such as NiMnSb (nickel-manganese-niobium), PtMnSb(platinum manganese-antimony) or the like can be used.

[0090] It is preferable that the magnetization fixed layer 5 comprisingthese materials has a unidirectional anisotropy (shape anisotropy), andthe magnetic layer 3 a and the intermediate layer 3 b each have auniaxial anisotropy. It is preferable that these layers have a thicknessin the range of 0.1 nm to 100 nm. Further, each of the ferromagneticlayer 5, 3 a and 3 b must have a film thickness in which it is notchanged to superparamagnetism, and it is therefore preferable that thefilm thickness is 0.4 nm or more.

[0091] Further, it is preferable that magnetization of a ferromagneticlayer used as the magnetization fixed layer 5 is fixed by adding ananti-ferromagnetic film to the layer. Such an anti-ferromagnetic filmcan comprise Fe (iron)—Mn (manganese), Pt (platinum—Mn (magnanese), Pt(platinum)—Cr (chromium)—Mn (manganese), Ni (nickel)—Mn (manganese), Ir(iridium)—Mn (manganese), NiO (nickel oxide), Fe₂O₃ (iron oxide) or thelike.

[0092] Furthermore, the magnetic characteristic of magnetic materialused may be adjusted by adding thereto non-magnetic element such as Ag(silver), Cu (copper), Au (gold), Al (aluminum), Mg (magnesium), Si(silicone), Bi (bismuth), Ta (tantalum), B (boron), C (carbon), O(oxygen), N (nitrogen), Pd (palladium), Pt (platinum), Zr (zirconium),Ir (iridium), w (tungsten), Mo (molybdenum), Nb (niobium) or the like.Besides, various physical properties such as crystallization, mechanicalproperties, chemical properties or the like can be adjusted.

[0093] On the other hand, a stacked layer film comprising aferromagnetic layer and a non-magnetic layer may be used as themagnetization fixed layer 5, the magnetic layer 3 a or the intermediatelayer 3 b. For example, a film having a three-layered structureincluding a ferromagnetic layer/a non-magnetic layer/a ferromagneticlayer or a multi-layered film with three or more layers may be used. Inthis case, it is preferable that an anti-ferromagnetic interaction actsto the ferromagnetic layers sandwiching the non-magnetic layer.

[0094] More specifically, as means for fixing magnetization of amagnetic layer in one direction, a stacked film having a three-layeredstructure comprising Co or Co—Fe/Ru (ruthenium)/Co or Co—Fe, a stackedfilm having a three-layered structure comprising Co (Co—Fe)/Ir(iridium)/Co (Co—Fe), a stacked film having a three-layered structurecomprising Co or Co—Fe/Os (osmium)/Co or Co—Fe, a stacked film having athree-layered structure comprising Co or Co—Fe/Re (rhenium)/Co or Co—Fe,a stacked film having a three-layered structure comprising an amorphousmaterial layer such as Co—Fe—B/Ru (ruthenium)/an amorphous materiallayer such as Co—Fe—B, a stacked film having a three-layered structurecomprising an amorphous material layer such as Co—Fe—B/Ir (iridium)/anamorphous material layer such as Co—Fe—B, a stacked film having athree-layered structure comprising an amorphous material layer such asCo—Fe—B/Os (osmium)/an amorphous material layer such as Co—Fe—B, or astacked film having a three-layered structure comprising an amorphousmaterial layer such as Co—Fe—B/Re (rhenium)/an amorphous material layersuch as Co—Fe—B is used. In case that such a stacked film is used as themagnetization fixed layer, it is preferable that an anti-ferromagneticfilm is provided adjacent to the stacked film. In this case, also, as amaterial for the anti-ferromagnetic film, Fe—Mn, Pt—Mn, Pt—Cr—Mn, Ni—Mn,Ir—Mn, NiO, Fe₂O₃ or the like can be used in the same manner asdescribed above. With this structure, magnetization of the magnetizationfixed layer 5 is hardly influenced by a current magnetic field from abit line or a word line, so that the magnetization direction is firmlyfixed. Further, stray field from the magnetization fixed layer 5 can bereduced (or adjusted), and magnetization shifting of the magneticrecording layer 3 a can be adjusted by changing the film thicknesses ofthe two ferromagnetic layers forming the magnetization fixed layer 5. Itis necessary to set the film thickness of each ferromagnetic layer tosuch a film thickness where it is not changed to superparamagnetism, andit is more preferable that the film thickness is in the range of 0.4 nmor more.

[0095] In addition, as the magnetic recording layer 3 c, a two-layeredstructure such as a soft magnetic layer/a ferromagnetic layer, or athree-layered structure such as a ferromagnetic layer/a soft magneticlayer/a ferromagnetic layer may be used. Such a preferable effect that,even if a cell width of a magnetic recording layer which is a memorycell becomes submicron or less, it is unnecessary to increase powerconsumption of a current magnetic field, can be obtained by using athree-layered structure such as a ferromagnetic layer/a non-magneticlayer/a ferromagnetic layer or a five-layered structure such as aferromagnetic layer/a non-magnetic layer/a ferromagnetic layer/ anon-magnetic layer/a ferromagnetic layer as the magnetic recording layer3 c to control the strength of interaction of interlayer of theferromagnetic layer. In this case, the kind and the film thickness ofthe ferromagnetic layer may be changed.

[0096] In particular, it is more preferable that, when Co—Fe, Co—Fe—Nior Fe rich Ni—Fe which increases a MR ratio is used in the ferromagneticlayer close to the tunnel barrier film 4 and Ni rich Ni—Fe, Ni richNi—Fe—Co or the like is used in the ferromagnetic substance which doesnot come in contact with the tunnel barrier film 4, a switching magneticfield can be reduced while the MR rate is kept large. As thenon-magnetic material, Ag (silver), Cu (copper), Au (gold), Al(aluminum), Ru (ruthenium), Os (osmium), Re (rhenium), Si (silicon), Bi(bismuth), Ta (tantalum), B (boron), C (carbon), Pd (palladium), Pt(platinum), Zr (zirconium), Ir (iridium), W (tungsten), Mo (molybdenum),Nb (niobium) or alloy thereof can be used.

[0097] The magnetic characteristic of the magnetic recording layer 3 acan be adjusted by adding such non-magnetic element as Ag (silver), Cu(copper), Au (gold), Al (aluminum), Ru (ruthenium), Os (osmium), Re(rhenium), Mg (magnesium), Si (silicon), Bi (bismuth), Ta (tantalum), B(boron), C (carbon), C (carbon), O (oxygen), N (nitrogen), Pd(palladium), Pt (platinum), Zr (zirconium), Ir (iridium), W (tungsten),Mo (molybdenum), Nb (niobium) or the like to the magnetic material.Besides, various physical properties such as crystallization, mechanicalproperties, chemical properties or the like can be adjusted.

[0098] On the other hand, when the TMR element is used as themagneto-resistance effect element, various insulators (dielectrics) suchas Al₂O₃ (aluminum oxide), SiO₂ (silicon oxide), MgO (magnesium oxide),AlN (aluminum nitride), Bi₂O₃ (bismuth oxide), MgF₂ (magnesiumfluoride), CaF₂ (calcium fluoride), SrTiO₂ (titanium oxide/strontium),AlLaO₃ (lanthnum oxide/aluminum), Al—N—O (aluminum oxide-aluminumnitride) or the like can be used as the insulating layer (or thedielectric layer) serving as the tunnel barrier layer 4 provided betweenthe magnetization fixed layer 5 and the magnetic recording layer 3 a.

[0099] These insulators are not required to have completely accuratecomposition in view of stoichiometry, and they may include excess ordeficiency of oxygen, nitrogen, fluoride or the like. Further, it ispreferable that the thickness of the insulating layer (dielectric layer)4 is as thin as a tunnel current flows. It is preferable that thethickness is actually 10 nm or less.

[0100] Such a magneto-resistance effect element can be formed on apredetermined substrate by using such an ordinary thin film formingprocess such as various sputtering processes, vapor depositingprocesses, molecular beam epitaxy or the like. In this case, as thesubstrate, a substrate comprising Si (silicon), SiO₂ (silicon oxide),Al₂O₃ (aluminum oxide), spinel, AlN (aluminum nitride) or the like canbe used.

[0101] Further, a layer comprising Ta (tantalum), Ti (titanium), Pt(platinum), Pd (palladium), Au (gold), Ti (titanium) /Pt (platinum), Ta(tantalum)/ Pt (platinum), Ti (titanium)/ Pd (palladium), Ta (tantalum)/Pd (palladium), Cu (copper), Al (aluminum)-Cu (copper), Ru (ruthenium),Ir (iridium) or Os (osmium) may be provided on the substrate as aunderground layer or a protective layer for the hard mask or the like.

Second Embodiment

[0102] Next, a magnetic memory according to a second embodiment of thepresent invention will be explained with reference to FIGS. 14A and 14B.FIG. 14A is a view showing a structure of a unit memory cell in amagnetic memory according to this embodiment, and FIG. 14B is asectional view of the unit memory cell taken along line A-A shown inFIG. 14A. A magnetic memory according to this embodiment is providedwith a plurality of bit lines BL (one bit line BL shown in FIGS. 14A and14B), a plurality of word lines WL (one word line WL shown in FIGS. 14Aand 14B) crossing these bit lines BL and a plurality of memory cell (onememory cell (unit cell) shown in FIGS. 14A and 14B) provided atrespective crossing points of the bit lines BL and the word lines WL.That is, the memory cells are arranged in a matrix shape to form amemory array. Each memory cell is provided with a storage element 2comprising a magneto-resistance effect element and provided at acrossing point of a bit line BL and a word line WL and a reading cellselecting transistor 18. The reading cell selecting transistor 18comprises a source /drain regions 18 a/18 b and a gate electrode 18 c.

[0103] The storage element 2 used in this embodiment is the TMR elementexplained in each of the first embodiment or its modified embodiments.That is, a T-shaped magnetization free layer constituting one endportion of the TMR element 2 is provided adjacent to a bit line BLserving as a writing wiring. Also, a yoke 8 is provided on the oppositeside of the bit line BL from the T-shaped magnetization free layer. Anopposite end portion of the TMR element 2 from the T-shapedmagnetization free layer is connected to one region 18 a of thesource/drain regions of the reading cell selecting transistor 18 via aleading electrode 12 and a connection plug 14.

[0104] The word line WL is disposed below the leading electrode 12 viaan insulating film (not shown), and it is covered with a yoke 22.

[0105] Writing of data into the TMR element 2 constituting a memory cellis conducted by a magnetic field obtained by causing writing currents toflow into a corresponding bit line BL and a corresponding word line WLto form current magnetic fields and compose them. Reading of data fromthe TMR element 2 constituting the memory cell is conducted by turningON the reading cell selecting transistor 18 of the memory cell to causea sense current to flow in the bit line BL via the TMR element 2.

[0106] Since the magnetic memory according to the second embodiment usesone TMR element of the first embodiment and its modifications as thestorage element, a writing current can be reduced and an excellentthermal stability can be achieved. Further, when the intermediate layerconstituting the TMR element is constituted as a multi-layered filmwhere a magnetic layer and a non-magnetic layer have been stackedalternatively, a MR ratio can be made high and a high output can beachieved.

Third Embodiment

[0107] Next, a magnetic memory according to a third embodiment of thepresent invention will be explained with reference to FIGS. 15A and 15B.FIG. 15A is a view showing a structure of a unit memory cell of amagnetic memory according to this embodiment and FIG. 15B is a sectionalview of the unit memory cell taken along line A-A shown in FIG. 15A. Amagnetic memory according to this embodiment is constituted such thatthe yoke 8 provided on the bit line BL also extends on side portions ofthe bit line BL shown in FIGS. 14A and 14B in the magnetic memoryaccording to the second embodiment shown in FIGS. 14A and 14B. Thereby,a writing current can be further reduced as compared with that in thesecond embodiment. Incidentally, the T-shaped magnetization free layerof the TMR element 2 and the yoke are not connected to each other, and amagnetic interaction therebetween does not occur while no current flowsin the bit line BL.

[0108] The magnetic memory according to this embodiment of the presentinvention can attain an excellent thermal stability like the case in thesecond embodiment.

Fourth Embodiment

[0109] Next, a magnetic memory according to a fourth embodiment will beexplained with reference to FIGS. 16A and 16B. FIG. 16A is a sectionalview showing a structure of a unit memory cell in a magnetic memoryaccording to this embodiment, and FIG. 16B is a sectional view of theunit memory cell taken along line A-A shown in FIG. 16A. A magneticmemory according to this embodiment is constituted such that theT-shaped magnetization free layer constituting the TMR element 2 isprovided adjacent to the word line WL instead of the bit line BL and anopposed end portion of the TMR element 2 from the T-shaped magnetizationfree layer is connected to the source region 18 a of the reading cellselecting transistor 18 via the leading electrode 12 and the connectionplug 14 in the magnetic memory in the second embodiment. A bit line BLis disposed above the leading electrode 12 via an insulating film (notshown). A yoke 8 is provided on the bit line BL so as to extend to sideportions of the leading electrode 12.

[0110] By employing such a structure that the yoke 8 extends near to theTMR element 2 in this manner, a writing current can be further reducedand a low power consumption can be achieved. Further, an excellentthermal stability can be achieved like the second embodiment.

[0111] In the second to fourth embodiments, it is preferable in order toachieve a further massive bulk memory that a memory cell allay ismulti-layered using an architecture which allows stacking of the memorycell array.

Fifth Embodiment

[0112] Next, a magnetic memory according to a fifth embodiment of thepresent invention will be explained with reference to FIGS. 17A, 17B and17C. FIG. 17A is a sectional view showing a structure of a magneticmemory according to this embodiment, FIG. 17B is a view showing astructure of a unit memory cell of the magnetic memory according to thisembodiment, and FIG. 17C is a sectional view of the unit memory celltaken along line A-A shown in FIG. 17B.

[0113] A magnetic memory according to this embodiment has a structurethat TMR elements 2 are respectively connected to a reading/writing bitline BL in a parallel manner via diodes 9. Incidentally, the TMR elementused in this embodiment is either one of the TMR elements of the firstembodiment and its modifications. The other ends of the respective TMRelements 2 are connected with reading/writing word lines WL.Incidentally, the T-shaped magnetization free layer constituting the TMRelement 2 is provided adjacent to the word line WL. An opposite side endof the TMR element 2 from the T-shaped magnetization free layer isconnected to the bit line BL via the diode 9.

[0114] At a time of reading, a bit line BL and a word line WL connectedto a target TMR element 9 are selected by respective selectingtransistors STB and STw and a current flowing in the target TMR element2 is detected by a sense amplifier SA. Further, at a time of writing, abit line BL and a word line WL connected to a target TMR element 2 areselected by respective selecting transistors STB and STw and a writingcurrent is caused to flow. At this time, a writing magnetic fieldobtained by composing magnetic fields respectively generated in the bitline BL and the word line WL turns magnetization of the magneticrecording layer of the TMR element 2 in a predetermined direction toperform writing.

[0115] The diode 9 serves to shut off by-pass currents flowing throughthe other TRM elements 2 arranged in a matrix manner at a time ofreading or writing.

[0116] Incidentally, in FIG. 17B, only a bit line BL, a TMR element 2, adiode 9 and a word line WL are shown for simplification and the otherelements are omitted. A shown in FIG. 17B, writing is conducted usingthe bit line BL and the word line WL orthogonal to each other. The bitline BL and the word line WL have yokes 8 and 22 formed thereon,respectively. Such a structure is employed that the yokes 8 and 22extend in the vicinity of the TMR element 2. Since the yokes coveringthe bit line BL and the word line WL can be caused to approach to theT-shaped magnetization free layer of the TMR element, writing can beconducted with low power consumption and with a low current. Further,since the TMR element having the T-shaped magnetization free layer isused, an excellent thermal stability can be achieved.

[0117] Incidentally, in order to realize a further massive bulk memory,it is desirable that a memory array is multi-layered using anarchitecture which allows multi-layer of the memory array.

Sixth Embodiment

[0118] Next, a magnetic memory according to a sixth embodiment of thepresent invention will be explained with reference to FIGS. 18A, 18B and18C. FIG. 18A is a sectional view showing a structure of a magneticmemory according to this embodiment, FIG. 18B is a view showing astructure of a unit memory cell of the magnetic memory according to thisembodiment, and FIG. 18C is a sectional view of the unit memory celltaken along line A-A shown in FIG. 18B.

[0119] A magnetic memory according to this embodiment has a “laddertype” structure where a plurality of TMR elements 2 are connected inparallel between a reading/writing bit line Bw and a reading bit lineBr. Further, the writing word lines W is wired in the vicinity of eachTMR element 2 in a direction orthogonal to the bit line Bw.

[0120] Writing in the TMR element 2 can be performed by causing acomposite magnetic field comprising a magnetic field generated bycausing a writing current to flow in the writing bit line Bw and amagnetic field generated by causing a writing current to flow in thewriting word line WL to act on the magnetic recording layer of the TMRelement 2.

[0121] On the other hand, when reading is conducted, a voltage isapplied between the bit line Bw and the bit line Br. Thereby, currentsare caused to flow in all the TMR elements 2 connected in parallelbetween the bit lines Bw and Br. While the sum of the currents beingdetected by the sense amplifier SA, a writing current is applied to theword line WL close to the target TMR element 2, so that themagnetization of the magnetic recording layer of the target TMR element2 is rewritten in a predetermined direction. By detecting a currentchange occurring at this time, reading of the target TMR element 2 canbe conducted.

[0122] That is, when the magnetization direction of the magneticrecording layer before re-writing is the same as that of the magneticrecording layer after re-writing, a current detected by the senseamplifier SA does not vary. However, when the magnetization direction ofthe magnetic recording layer is inverted before and after re-writing, acurrent detected by the sense amplifier SA varies due to amagneto-resistance effect. Thus, the magnetization direction of themagnetic recording layer before rewriting, namely, stored data can beread out in this manner.

[0123] Incidentally, this method corresponds to a case that stored datais changed at a time of reading, so-called “destructive reading”.

[0124] On the other hand, when a structure such as a magnetization freelayer/an insulating layer (non-magnetic layer)/a magnetic recordinglayer is employed as the structure of the magneto-resistance effectelement, a so-called “non-destructive reading” will be made possible.That is, in case that a magneto-resistance effect element having thisstructure is used, the magnetization direction is recorded in themagnetic recording layer, and the magnetization direction of themagnetic recording layer can be read out at a time of reading-out bychanging the magnetization direction of the magnetization free layerproperly to compare sense currents before and after the change with eachother. Incidentally, it is necessary to make design such that amagnetization (flux) inverting magnetic field of the magnetization freelayer is smaller that that of the magnetic recording layer.

[0125] Incidentally, in FIG. 18B, only the bit lines Br and Bw, the TWRelement 2 and the word line WL are shown for simplification, and theother elements have been omitted. As shown in FIG. 18B, writing isconducted by using the bit lines Br and Bw and the word line WL.

[0126] Incidentally, in this embodiment, the T-shaped magnetization freelayer constituting the TMR element 2 is provided adjacent to the bitline Bw. Such a structure is employed that an opposite end portion ofthe TMR element 2 from the T-shaped magnetization free layer isconnected to the bit line Br. The word line WL is disposed above the bitline Br via an insulating film (not shown). A yoke 22 is provided on theword line WL so as to extend up to side portions of the bit line Br, andyoke 8 is provided on the bit line Bw so as to approach to the T-shapedmagnetization free layer of the TMR element 2. Since the yokes coveringthe bit line Br and the word line WL can be caused to approach to theT-shaped magnetization free layer of the TMR element in this manner,writing can be conducted with low power consumption and a low current.Further, since the TMR element having the T-shaped magnetization freelayer is used, an excellent thermal stability can be achieved.

Seventh Embodiment

[0127] Next, a magnetic memory according to a seventh embodiment of thepresent invention will be explained with reference to FIGS. 19A and 19B.FIG. 19A is a view showing a structure of a memory cell array of amagnetic memory according to this embodiment and FIG. 19B is a sectionalview of the memory cell array taken along line A-A shown in FIG. 19A. Amagnetic memory according to this embodiment is constituted so as toconduct a simple matrix/double tunnel type reading. In this embodiment,TMR elements 2 ₁ and 2 ₂ with a T-shaped magnetization free layer arerespectively disposed above and below a bit line BL. In case ofconducting double tunnel type reading, a current is caused to flowbetween a reading bit line Br1 and a reading bit line Br2 anddetermination is made about the data “1” or “0” depending on whetherresistance to the current flow is large or small. Accordingly, since aspin direction of a magnetic layer of a T-shaped magnetization freelayer 3 coming in contact with a tunnel barrier layer 4 allows currentflow in the bit line BL and the word line WL to conduct recording in anopposite direction, spin directions (magnetization directions) of themagnetic layers of the magnetization fixed layers 5 of the upper andlower TMR elements 2 ₁ and 2 ₂ coming in contact with the tunnel barrierlayers 4 eventually become anti-parallel. Such a structure can be easilyfabricated, for example, by using a synthetic pin structure formagnetization fixation of a one-side TMR element. Incidentally, yokes 8are provided at side portions of the bit line BL, and yokes 22 ₁ and 22₂ are provided on word line WL1 and WL2.

[0128] The magnetic memory of this embodiment also has reduced powerconsumption and an excellent thermal stability.

Eighth Embodiment

[0129] Next, a magnetic memory according to an eighth embodiment of thepresent invention will be explained with reference to FIGS. 20A and 20B.FIG. 20A is a view showing a structure of a memory cell array of amagnetic memory according to this embodiment, and FIG. 20B is asectional view showing the memory cell array taken along line A-A shownin FIG. 20A. A magnetic memory according to this embodiment isconstituted so as to conduct a simple matrix/differential amplifyingtype reading. In this embodiment, TMR elements 2 ₁ and 2 ₂ with aT-shaped magnetization free layer are provided above and below a bitline BL in the same manner as the seventh embodiment.

[0130] In writing, spin directions of magnetic layers of respectiveT-shaped magnetization free layers of the TRM elements 2 ₁ and 2 ₂coming in contact with the tunnel barrier layers allow current flow inthe bit line BL and the word lines WL1 and WL2 to conduct recording inan opposite direction. In reading, a current is branched from the bitline BL to a reading bit line BL1 and a reading bit line BL2 and thecurrents branched are differentially amplified by a differentialamplifier 40. Therefore, such a design is made that spin directions(magnetization directions) of the magnetic layers of the magnetizationfixed layers 5 coming in contact with the tunnel barrier layers 4 havethe same direction while the spin directions of the magnetic layers ofthe T-shaped magnetization free layers 3 coming in contact with thetunnel barrier layers 4 have anti-parallel directions.

[0131] Incidentally, yokes 8 are provided at side portions of the bitline BL and yokes 22 ₁ and 22 ₂ are respectively provided on the wordlines WL1 and WL2.

[0132] The magnetic memory of this embodiment also has reduced powerconsumption and an excellent thermal stability.

Ninth Embodiment

[0133] Next, a magnetic memory according to a ninth embodiment of thepresent invention will be explained with reference to FIGS. 21A and 21B.FIG. 21A is a view showing a structure of a unit memory cell of amagnetic memory according to this embodiment, and FIG. 21B is asectional view showing the unit memory cell taken along line A-A shownin FIG. 21A. A magnetic memory according to this embodiment is providedwith a plurality of common bit lines BL, a plurality of reading wordlines Wr crossing these bit lines BL, and memory cells provided atrespective crossing points for the bit lines BL and the word line Wr.Each memory cell is provided with a cell bit line 30 branched from thecommon bit line BL, a TMR element 2 with a T-shaped magnetization freelayer 3 and a writing cell selecting transistor 19.

[0134] The cell bit line 30 is provided with a first wiring portion 30 abranched from the common bit line BL, a second wiring portion 30 b whichhas one end connected to the first wiring portion 30 a and to which aT-shaped magnetization free layer 3 of the TMR element 2 is providedadjacent, and a third wiring portion 30 c which has one end connected tothe other end of the second wiring portion 30 b and has the other endconnected to a diffusion region 19 a of one of the source and the drainof a writing cell selecting transistor 19. The second wiring portion 30b is provided with a yoke 24. A diffusion region 19 b of the other ofthe source and the drain of the writing cell selecting transistor 19 isconnected with a connection plug. A current is caused to flow in thegate 19 c of the writing cell selecting transistor 19 at a time ofwriting so that the writing cell selecting transistor 19 is turned ON.

[0135] Further, a reading word line Wr is connected to an opposite endportion of the TMR element 2 from the T-shaped magnetization free layer3.

[0136] At a time of writing, the cell selecting transistor 19 is turnedON to cause a current pulse to flow in the common bit line BL and acurrent magnetic field is effectively applied to the T-shapedmagnetization free layer 3 coming in contact with the cell bit line 30b, thereby reversing the direction of the spin. At this time, since theyoke 24 has been provided, a writing current value can be reduced moreefficiently.

[0137] Incidentally, in this embodiment, a writing current is caused toflow in only the common bit line BL at a time of writing.

[0138] The magnetic memory of this embodiment also has reduced powerconsumption and an excellent thermal stability.

Tenth Embodiment

[0139] Next, a magnetic memory according to a tenth embodiment of thepresent invention will be explained with reference to FIGS. 22A and 22B.FIG. 22A is a view showing a structure of a unit memory cell of amagnetic memory according to this embodiment, and FIG. 22B is asectional view showing the unit memory cell taken along line A-A shownin FIG. 22A. A magnetic memory according to this embodiment isconstituted such that the yoke 24 provided on the second wiring portion30 b of the cell bit line 30 is removed from the ninth embodiment shownin FIGS. 21A and 21B and a writing word line WL has been provided abovethe second wiring portion 30 b via an insulating film (not shown).Incidentally, the writing word line WL is provided with a yoke 22.

[0140] Accordingly, in this embodiment, a writing current is caused toflow in not only the common bit line BL but also the writing word lineWL at a time of writing. For this reason, a current per wiring can bereduced.

[0141] The magnetic memory of this embodiment also has reduced powerconsumption and an excellent thermal stability.

Eleventh Embodiment

[0142] Next, a magnetic memory according to an eleventh embodiment ofthe present invention will be explained with reference to FIGS. 23A and23B. FIG. 23A is a view showing a structure of a unit memory cell of amagnetic memory according to the embodiment, and FIG. 23B is a sectionalview showing the unit memory cell taken along line A-A shown in FIG.23A. A magnetic memory according to this embodiment is constituted suchthat the reading word line Wr which has been directly connected to theopposite end portion of the TMR element 2 from the T-shapedmagnetization free layer 3 is connected to the opposite side via aleading electrode 13 and a connection plug 15 and a writing word line WLis provided below an opposite end portion of the TMR element 2 from theT-shaped magnetization free layer 3 via an insulating film (not shown)in the ninth embodiment shown in FIGS. 21A and 21B. The reading wordline Wr and the writing word line WL are formed so as to be positionedon the same layer. Incidentally, the reading word line Wr and thewriting word line WL are respectively provided with yokes 23 and 22.

[0143] Accordingly, in this embodiment, a writing current is caused toflow in not only the common bit line BL but also the writing word lineWL at a time of writing. For this reason, a current per wiring can bereduced.

[0144] The magnetic memory of this embodiment also has reduced powerconsumption and an excellent thermal stability.

Twelfth Embodiment

[0145] Next, a magnetic memory according to a twelfth embodiment of thepresent invention will be explained with reference to FIGS. 24A and 24B.FIG. 24A is a view showing a structure of a unit memory cell of amagnetic memory according to the embodiment, and FIG. 24B is a sectionalview showing the unit memory cell taken along line A-A shown in FIG.24A. A magnetic memory according to this embodiment is constituted suchthat the yoke 24 provided on the second wiring portion of the cell bitline 30 is also caused to extend to side portions of the second wiringportion 30 b in the eleventh embodiment shown in FIGS. 23A and 23B.

[0146] This embodiment can further be reduced in writing current ascompared with the eleventh embodiment. The magnetic memory of thisembodiment also has reduced power consumption and an excellent thermalstability.

Thirteenth Embodiment

[0147] Next, a magnetic memory according to a thirteenth embodiment ofthe present invention will be explained with reference to FIG. 25. FIG.25 is a view showing a structure of a unit memory cell of a magneticmemory according to this embodiment. A magnetic memory according to thisembodiment is constituted such that the connection position between theT-shaped magnetization free layer 3 of the TMR element 2 and the secondwiring portion 30 b of the cell bit line 30 is changed from a positionbelow the second wiring portion 30 b to a position above the same andthe position where the yoke 24 is provided is changed from a positionabove the second wiring portion 30 b to a position below the same in thetwelfth embodiment shown in FIGS. 24A and 24B. For this reason, theleading electrode 13, the connection plug 15, the reading word line Wrand the writing word line WL have been provided above the second wiringportion 30 b.

[0148] The magnetic memory of this embodiment also has reduced powerconsumption and an excellent thermal stability.

Fourteen Embodiment

[0149] Next, a magnetic memory according to a fourteenth embodiment ofthe present invention will be explained with reference to FIG. 26. FIG.26 is a view showing a structure of a unit memory cell of a magneticmemory according to this embodiment. A magnetic memory according to thisembodiment is constituted such that the reading word line Wr isconnected to an opposite end portion of the TMR element 2 from theT-shaped magnetization free layer and the writing word line WL isarranged above the reading word line Wr via an insulating film (notshown) in the thirteenth embodiment shown in FIG. 25. A yoke 22extending up to the vicinity of the magnetization fixed layer of the TMRelement 2 is provided on the writing word line WL.

[0150] The magnetic memory of this embodiment also has reduced powerconsumption and an excellent thermal stability.

[0151] In the magnetic memories according to the tenth to fourteenthembodiments shown in FIGS. 22A to 26, reading is conducted in the samemanner as the magnetic memory of the ninth embodiment shown in FIGS. 21Aand 21B.

Fifteenth Embodiment

[0152] Next, a magnetic memory according to a fifteenth embodiment ofthe present invention will be explained with reference to FIG. 27. FIG.27 is a view showing a structure of a unit memory cell of a magneticmemory according to the embodiment. A magnetic memory according to thisembodiment is constituted such that, instead of the reading word lineWr, a reading/writing word line WL is connected to an opposite endportion of the TMR element 2 from the T-shaped magnetization free layervia a diode 9 in the ninth embodiment shown in FIGS. 21A and 21B.Incidentally, the word line WL is covered with a yoke 22 except for aconnection surface with the diode 9.

[0153] The magnetic memory of this embodiment also has reduced powerconsumption and an excellent thermal stability.

Sixteenth Embodiment

[0154] Next, a magnetic memory according to a sixteenth embodiment ofthe present invention will be explained with reference to FIG. 28. FIG.28 is a view showing a structure of a unit memory cell of a magneticmemory according to the embodiment. A magnetic memory according to thisembodiment is constituted such that one region of the source region andthe drain region of the reading cell selecting transistor 18 isconnected to the reading word line Wr via a leading electrode 12 and aconnection plug 14 in the eleventh embodiment shown in FIGS. 23A and23B. A connection plug 16 connected to the other region of the sourceregion and the drain region of the reading cell selecting transistor 18is connected with a power source.

[0155] In the embodiment, reading is conducted by turning ON the readingcell selecting transistor 18 to apply a voltage between the common bitline BL and the power source connected to the connection plug 16,thereby reading a current flowing in the TMR element 2 by a senseamplifier (not shown).

[0156] The magnetic memory of this embodiment also has reduced powerconsumption and an excellent thermal stability.

Seventeenth Embodiment

[0157] Next, a magnetic memory according to a seventeenth embodiment ofthe present invention will be explained with reference to FIGS. 29A and29B. FIG. 29A is a view showing a structure of a unit memory cell of amagnetic memory according to this embodiment, and FIG. 29B is asectional view of the unit memory cell taken along line A-A shown inFIG. 29A. A magnetic memory according to the embodiment is constitutedsuch that the TMR element 2 and the yoke 24 are removed and the TMRelements 2 ₁ and 2 ₂ are provided above and below the second wiringportion 30 b of the cell bit line 30 in the ninth embodiment shown inFIGS. 21A and 21B. Such a structure is also employed in this embodimentthat the T-shaped magnetization free layers of the TMR elements 2 ₁ and2 ₂ are respectively connected to the second wiring portion 30 b, and areading bit line Br and a reading word line Wr are connected to oppositeend portions of the TMR elements 2 ₁ and 2 ₂ from the T-shapedmagnetization free layers.

[0158] The magnetic memory of this embodiment also has reduced powerconsumption and an excellent thermal stability.

Eighteenth Embodiment

[0159] Next, a magnetic memory according to an eighteenth embodiment ofthe present invention will be explained with reference to FIGS. 30A and30B. FIG. 30A is a view showing a structure of a unit memory cell of amagnetic memory according to the embodiment, and FIG. 30B is a sectionalview showing the unit memory cell taken along line A-A shown in FIG.30A. A magnetic memory according to the embodiment is constituted suchthat a reading word line Wr1 is provided instead of the reading bit lineBr connected to the TMR element 2 ₁, the reading word line Wr connectedto the TMR element 2 ₂ is changed to a reading word line Wr2, andreading currents flowing in the reading word lines Wr1 and Wr2 aredifferentially read out using the differential amplifier 40 in theseventeenth embodiment shown in FIGS. 29A and 29B.

[0160] The magnetic memory of this embodiment also has reduced powerconsumption and an excellent thermal stability.

Nineteenth Embodiment

[0161] Next, a manufacturing method of a TMR element according to anineteenth embodiment of the present invention will be explained withreference to FIGS. 31A to 32E. A manufacturing method according to thisembodiment is for manufacturing a TMR element according to the fourthmodification of the first embodiment shown in FIG. 6, and itsmanufacturing steps are shown in FIGS. 31A to 32E.

[0162] A lower wiring 50, a TMR film (or element) 52, a multi-layeredfilm 54 comprising a magnetic layer and a non-magnetic layeranti-ferromagnetically coupled, a metal film 56 comprising Pt or Ru, anda metal hard mask 58 were first formed sequentially on a substrate (notshown) (refer to FIG. 31A). In the embodiment, the lower wiring 50 was athree-layered film comprising Ta/Al—Cu/Ta, and the TMR film wasconstituted by stacking Ta (5 nm)/Ru (3 nm)/Ir—Mn (10 nm)/CoFe (3 nm)/Ru(1 nm)/CoFe (3.25 nm)/AlOx (1.2 nm)/CoNiFe (2 nm)/Ru (0.95 nm)/NiFe (2nm) from a bottom thereof. The multi-layered film 54 obtained byrepeating stacking of a non-magnetic layer with a film thickness of 2.45nm comprising Ru and a magnetic layer with a film thickness of 3 nmcomprising CoFeB ten times, the metal film 56 comprising Pt or Ru, andthe metal hard mask 58 with 50 nm comprising Ta were formed on the TMRfilm 52. Subsequently, anneal was conducted in a magnetic field,application of a resist was then conducted, and a resist pattern 60 wasformed by conducting PET on the resist, as shown in FIG. 31A.

[0163] Next, as shown in FIG. 31B, patterning of the metal hard mask 58was conducted by utilizing the resist pattern 60 as a mask with chlorinegas, for example, using RIE process. At this time, the etching wasstopped at the Ru or Pt film 56. Thereafter, as shown in FIG. 31C, theresist pattern 60 was peeled off and milling or RIE was conducted downto an anti-ferromagnetic layer comprising IrMn and constituting the TMRfilm by using the metal hard mask 58 as a mask, so thatjunction-separation is performed to a ferromagnetic tunnel junction. Aplane figure of the tunnel junction was a circle with an aspect ratio of1:1. The size of the junction had a diameter of 0.18 μm.

[0164] Next, as shown in FIG. 31D, a protective film 62 comprising SiOxwas formed. Subsequently, as shown in FIG. 31E, a resist is applied, PEPwas conducted to form a resist pattern 64, and patterning of the lowerelectrode 50 is conducted by utilizing the resist pattern 64 as a mask,for example, using RIE.

[0165] Next, as shown in FIG. 31F, after the resist pattern 64 wasremoved, an inter-layer insulating film 66 comprising SiOx was formed.

[0166] Next, as shown in FIG. 32A, the inter-layer insulating film 66was etched back to conduct planarization and expose either layer ofmultiple layers of Ru (2.45 nm) and CoFeB (3 nm) in an upper portion ofTMR film 54.

[0167] Next, as shown in FIG. 32B, after sputter-etching, a magneticlayer 68, a metal layer 70 comprising Pt or Ru, and a metal hard mask 72were sequentially formed by sputtering. Ni—Fe was used for the magneticlayer 68 and Ta was used for the hard mask 72.

[0168] Next, a resist pattern (not shown) was formed and the hard mask72 was patterned by utilizing the resist pattern as a mask and using RIE(refer to FIG. 32C). Subsequently, after the resist patterned wasremoved, the metal hard mask 72 was utilized as a mask and the Ni—Femagnetic layer 68 was formed in a shape (a mask-shaped octagon: aspectratio (long axis/short axis)/long axis=—2 μm and short axis=0.25 μm)shown in FIG. 11C.

[0169] Next, as shown in FIG. 32D, an upper wiring 74 and a magneticcovering layer (yoke) 76 were formed. Thereafter, a resist pattern (notshown) was formed on the yoke 76, the yoke and the upper wiring 74 werepatterned by utilizing the resist pattern as a mask, and a TMR elementhaving a T-shaped magnetization free layer shown in FIG. 32E wasmanufactured.

[0170] Thereafter, anneal was conducted in a magnetic field such that amagnetic field was applied in a long axis direction of the Ni—Femagnetic layer 68 just below the upper wiring 74. A pulse current wasapplied to the upper wiring 74 in a stepwise manner while it was beinggradually increased from a value of 0.01 mA. An element resistance wasmeasured for each step and a resistance change was observed when thepulse current was 0.27 mA. A pulse current was caused to flow in adirection of magnetization hard axis, a magnetic field of 10 Oe wasapplied in the direction of magnetization hard axis and a similarexperiment was conducted. Reserve was observed when the current pulsewas 0.15 mA. Thereafter, ten elements were maintained at 120° C. for oneweek while they were being kept in “1” state that a TMR elementresistance was high and ten elements were maintained at 120° C. for oneweek while they were being kept in “0” state that the TMR elementresistance was low. As result, reservation of data was confirmed inthese elements and the elements each developed desirable characteristicsas a non-volatile magnetic memory.

Twentieth Embodiment

[0171] Next, a manufacturing method of a TMR element according to atwentieth embodiment of the present invention will be explained withreference to FIGS. 33A to 34C. A manufacturing method according to thisembodiment is for manufacturing a TMR element according to the eighthmodified embodiment of the first embodiment shown in FIG. 10, and itsmanufacturing steps are shown in FIGS. 33A to 34C.

[0172] A magnetic covering layer (yoke) 80 and a lower wiring 82 wereformed on a substrate (not shown) by sputtering, a resist pattern (notshown) was formed, and patterning was conducted using the resistpattern. Then, SiOx was deposited and planarization was conducted by CMP(refer to FIG. 33A).

[0173] Next, as shown in FIG. 33B, a magnetic layer 84, a multi-layeredfilm 86 formed by stacking a magnetic layer and a non-magnetic layernon-ferromagnetically coupled, a TMR film 88, a metal film 90 comprisingPt or Ru, and a metal hard mask 92 were formed. In this embodiment, themagnetic covering layer 80 comprised Ni—Fe, the lower wiring 82 was athree-layered film comprising Ta/Al—Cu/Ta, the magnetic layer 84 was athree-layered film comprising Ni—Fe (3 nm)/Ru (1.5 nm)/Ni—Fe (2 nm), themulti-layered film 86 was a layer obtained by repeating stacking ofCoFeB (3 nm) and Ru (2.45 nm) ten times, and the TMR film 88 was a filmobtained by stacking Pt—Mn (14 nm)/CoFe (3 nm)/Ru (1 nm)/CoFe (3.25nm)/AlOx (1.2 nm)/CoNiFe (2 nm)/Ru (0.95 nm)/NiFe (2 nm) in this orderfrom the top. A metal film 90 comprising Pt or Ru and a metal hard mask92 with a film thickness of 50 nm comprising Ta were formed on the TMRfilm 88.

[0174] Subsequently, after anneal was conducted in a magnetic field, aresist pattern (not shown) was formed, and anisotropic etching then wasconducted on the metal hard mask 92 by utilizing the resist pattern as amask with chlorine gas (refer to FIG. 33C). At this time, the etchingwas stopped at the metal film 90 comprising Ru or Pt.

[0175] Thereafter, junction-separation was conducted on theferromagnetic tunnel junction by peeling off the resist pattern andutilizing the metal hard mask 92 as a mask to conduct milling or RIEdown to an intermediate portion of the multi-layered film 86 of tenlayers comprising CoFeB (3 nm)/Ru (2.45 nm) (refer to FIG. 33D). Theplane shape of the tunnel junction was formed in a circular shape withan aspect ratio of 1:1. The size of the tunnel junction had a diameterof 0.18 μm.

[0176] Subsequently, as shown in FIG. 33E, a SiOx film 94 was formed.Thereafter, a resist pattern (not shown) was formed and the SiOx film 94was patterned by utilizing the resist pattern as a mask and using, forexample, RIE process.

[0177] Next, after the resist pattern was removed, the remaining somelayers of the multi-layered film 86 comprising CoFeB (3 nm)/Ru (2.45 nm)was patterned by utilizing the SiOx film 94 patterned as a mask andusing milling or RIE process, and the Ni—Fe layer 84 was patterned(refer to FIG. 33F). A plane structure was a shape (a mask-shapedoctagon: aspect ratio (long axis/short axis)=1, short axis=longaxis=0.25 μm) as shown in FIG. 11E.

[0178] Next, as shown in FIG. 34A, after a SiOx film 96 was deposited,planarization was conducted by using CMP and etch back and exposure of aTa film constituting the metal hard mask 92 was conducted (refer to FIG.34B).

[0179] Thereafter, after sputter-etching was conducted, an upper wiring98 was formed to manufacture a TMR element with a T-shape magnetizationfree layer having a structure shown in FIG. 34C.

[0180] Thereafter, anneal was conducted in a magnetic field and amagnetic field was applied in a direction of magnetization easy axis ofthe Ni—Fe layer and (CoFeB (3 nm)/Ru (2.45 nm)) X layer just below theupper wiring 98. A pulse current was applied to the upper wiring 98 in astepwise manner while it was being gradually increased from a value of0.01 mA. An element resistance was measured for each step and aresistance change was observed when the pulse current was 0.26 mA. Apulse current was caused to flow in a direction of magnetization hardaxis, a magnetic field of 10 Oe was applied in the direction ofmagnetization hard axis and a similar experiment was conducted. Reservewas observed when the current pulse was 0.14 mA. Thereafter, ten TMRelements were maintained at 120° C. for one week while they were beingkept in “1” state that a TMR element resistance was high and ten TMRelements were maintained at 120° C. for one week while they were beingkept in “0” state that the TMR element resistance was low. As result,reservation of data was confirmed in these elements and the elementseach developed desirable characteristics as a non-volatile magneticmemory.

Twenty-First Embodiment

[0181] A TMR element with the T-shaped magnetization free layer shown inFIGS. 35A and 35B, which was used in a magnetic memory according to theseventh and the eighth embodiments shown in FIGS. 19A to 20B wasmanufactured as a twenty-first embodiment and performances thereof wereexamined. FIG. 35A shows a structure for examining a double junctionreading architecture and FIG. 35B shows a structure for examining adifferential reading architecture. A manufacturing process is basicallyconstituted with a combination of the nineteenth embodiment and thetwentieth embodiment. The covering magnetic layer 8 of the bit line BLcan be easily manufactured by, after patterning the bit line BL, formingthe covering magnetic layer 8 to conduct milling the same from avertical direction. Various materials used in this embodiment were thesame materials as used in the nineteenth and twentieth embodiments. Thesize and the shape of the element were similar to those in the twentiethembodiment.

[0182] As described above, the case of the double junction reading andthe case of the differential reading are different in direction of spinof a magnetization fixed layer coming in contact with a tunnel barrierlayer. This is because the magnetization fixed layer can be easilymanufactured by using a multi-layered film of a magnetic layer/anon-magnetic layer anti-ferromagnetically coupled.

[0183] A pulse current was applied to the bit line BL shown in FIG. 35Ain a stepwise manner while it was being gradually increased from 0.01mA. Element resistances of the upper and lower TMR elements 2 ₁ and 2 ₂were measured for each step and changes of both the resistances thereofwere observed when the pulse current was 0.28 mA. A pulse current wascaused to flow in a direction of magnetization hard axis, a magneticfield of 10 Oe was applied in the direction of magnetization hard axisand a similar experiment was conducted. Inversion of both the upper andlower TMR elements 2 ₁ and 2 ₂ was observed when the current pulse was0.17 mA. Thereafter, ten elements were maintained at 120° C. for oneweek while they were being kept in “1” state that a TMR elementresistance was high and ten elements were maintained at 120° C. for oneweek while they were being kept in “0” state that the TMR elementresistance was low. As result, reservation of data was confirmed inthese elements and the elements each developed desirable characteristicsas a non-volatile magnetic memory. Further, in the double junctionreading, a reading signal became 1.6 times the cases of the nineteenthand twentieth embodiments and in the differential reading, a readingsignal became 2 times these cases, so that S/N ratio of reading was madeexcellent and desirable characteristics for a memory were developed.

Twenty-Second Embodiment

[0184] Next, a magnetic recording and reproducing apparatus according toa twenty-second embodiment of the present invention will be explained.The magneto-resistance effect element according to the first embodimentwhich has been explained with reference to FIGS. 1 to 12 and FIG. 36 canbe assembled in, for example, a magnetic head assembly of a recordingand reproducing integral type and can be mounted in a magnetic recordingand reproducing apparatus. In this case, such a structure is employedthat the magnetization directions of the magnetization free layer andthe magnetization fixed layer of the magneto-resistance effect elementare different from the magnetization direction of the magnetic memoryand they are substantially perpendicular to each other.

[0185]FIG. 37 is a schematic perspective view showing the arrangement ofsuch a magnetic recording and reproducing apparatus. A magneticrecording and reproducing apparatus 150 of the present invention is anapparatus in which a rotary actuator is used. In the drawing, a magneticdisk 200 for lateral or vertical recording is attached to a spindle 152and is rotated in a direction shown by an arrow A by a motor (not shown)which responds to control signals from an actuator control unit (notshown). The magnetic disk 200 may be configured as “keypad media” whichincludes a record layer for lateral or vertical recording and furtherincludes a soft magnetic layer deposited thereon. A head slider 153,which is used to record and reproduce information to be stored in themagnetic disk 200, is attached to a tip of a thin film shaped suspension154. The head slider 153 has the recording/reproducing head in FIG. 30built in around its tip.

[0186] When the magnetic disk 200 is rotated, a surface (ABS) of thehead slider 153 opposed to the medium is held apart from the surface ofthe magnetic disk 200 by a specific lifting distance.

[0187] The suspension 154 is connected to one end of an actuator arm 155which has a bobbin holding actuating coil (not shown). The actuator arm155 has the other end coupled to a voice coil motor 156 serving as alinear motor. The voice coil motor 156 is comprised of actuating coil(not shown) wound on the bobbin of the actuator arm 155 and a magneticcircuit which has a pair of permanent magnets opposed to each other withthe coil being nipped between them, and opposing yokes.

[0188] The actuator arm 155 is held by ball bearings (not shown) inupper and lower positions of a fixture shaft 157, and is slidablyrotated by the voice coil motor 156.

[0189]FIG. 38 is an enlarged perspective view showing part of themagnetic head assembly ahead of the actuator arm 155, in an orientationseen from the side of the disk. The magnetic head assembly 160 has anactuator arm 151 provided with a bobbin for holding actuating coil, andthe actuator arm 155 has its one end connected to the suspension 154.

[0190] The head slider 153, which has the aforementioned built-inrecording/reproducing head, is attached to a tip of the suspension 154.The suspension 154 has lead lines 164 for writing and reading signals,and the lead lines 164 and electrodes of the magnetic head incorporatedin the head slider 153 are electrically connected to one another. InFIG. 38, a reference numeral 165 denotes an electrode pad of themagnetic head assembly 160.

[0191] The embodiments of the present invention have been explainedabove with reference to the specific examples. However, the presentinvention is not limited to these embodiments. For example, any casethat the present invention can be implemented in the same manner as theabove and a similar effect or advantage thereof can be achieved bysuitable selection of specific material, film thickness, shape, size andthe like for a ferromagnetic substance layer, an insulating film, ananti-ferromagnetic substance layer, a non-magnetic metal layer, anelectrode or the like constituting the magneto-resistance effect elementwhich are made by those skilled in the art can be included in the scopeof the present invention.

[0192] Similarly, any case that the present invention can be implementedin the same manner as the above and a similar effect or advantagethereof can be achieved by suitable selection of structure, material,shape and size of each element constituting the magnetic memory of thepresent invention made by those skilled in the art can be included inthe scope of the present invention.

[0193] Further, a similar effect or advantage can be obtained byapplying the magneto-resistance effect element of the present inventionto a magnetic head or magnetic reproducing apparatus of not only alongitudinal magnetic recording system but also a vertical magneticrecording system.

[0194] Besides, any magnetic memory which can be changed in design onthe basis of the above-described magnetic memories as the embodiments ofthe present invention to be implemented by those skilled in the art areincluded in the scope of the present invention.

[0195] Incidentally, a sense current controlling element circuit forcontrolling a sense current caused to flow in the magneto-resistanceeffect element for reading information stored in the magneto-resistanceeffect element, a circuit for application of a writing pulse, a driverand the like have not been explained in the above embodiments, but thesemembers can be provided in the magnetic memory of the present invention.

[0196] As described above, according to the present invention, powerconsumption can be reduced and an excellent thermal stability can beachieved.

[0197] Additional advantages and modifications will readily occur tothose skilled in the art. Therefore, the invention in its broaderaspects is not limited to the specific details and representativeembodiments shown and described herein. Accordingly, variousmodifications may be made without departing from the spirit or scope ofthe general inventive concepts as defined by the appended claims andtheir equivalents.

What is claimed is:
 1. A magneto-resistance effect element comprising: afirst ferromagnetic layer serving as a magnetization fixed layer; amagnetization free layer comprising a second ferromagnetic layerprovided on one side of the first ferromagnetic layer, a thirdferromagnetic layer which is formed on an opposite side of the secondferromagnetic layer from the first ferromagnetic layer and has a filmface having an area larger than that of the second ferromagnetic layerand whose magnetization direction is changeable by an external magneticfield, and an intermediate layer which is provided between the secondferromagnetic layer and the third ferromagnetic layer and whichtransmits a change of magnetization direction of the third ferromagneticlayer to the second ferromagnetic layer; and a tunnel barrier layerprovided between the first ferromagnetic layer and the secondferromagnetic layer.
 2. The magneto-resistance effect element accordingto claim 1, wherein the second ferromagnetic layer and the thirdferromagnetic layer are magnetically coupled via the intermediate layer.3. The magneto-resistance effect element according to claim 1, whereinan aspect ratio of a plane shape of the third ferromagnetic layer iswithin a range from 1 to
 2. 4. The magneto-resistance effect elementaccording to claim 1, further comprising an anti-ferromagnetic layerformed on an opposite side of the first ferromagnetic layer from thetunnel barrier layer.
 5. The magneto-resistance effect element accordingto claim 1, wherein at least one ferromagnetic layer of the first tothird ferromagnetic layers is a stacked film where a ferromagnetic filmand a non-magnetic film are stacked alternatively.
 6. Themagneto-resistance effect element according to claim 1, wherein theintermediate layer is a single-layered ferromagnetic film or a stackedfilm where a ferromagnetic film and a non-magnetic film are stackedalternatively, and anti-ferromagnetic exchange coupling or ferromagneticexchange coupling exists, via the non-magnetic film, between theadjacent ferromagnetic films of the stacked film.
 7. Themagneto-resistance effect element according to claim 1, wherein thesecond ferromagnetic layer and the intermediate layer have the same filmface shape, and the third ferromagnetic layer magnetically contact withthe intermediate layer.
 8. A magneto-resistance effect elementcomprising: a first ferromagnetic layer serving as a magnetization fixedlayer; a magnetization free layer which is provided on one side of thefirst ferromagnetic layer, the magnetization free layer having a T-shapein a section perpendicular to a film face thereof taken along amagnetization easy axis of the magnetization free layer; and a tunnelbarrier layer provided between the first ferromagnetic layer and themagnetization free layer.
 9. The magneto-resistance effect elementaccording to claim 8, wherein the magnetization free layer comprises asecond ferromagnetic layer, a third ferromagnetic layer which is formedon an opposite side of the second ferromagnetic layer from the tunnelbarrier layer and has a film face having an area larger than that of thesecond ferromagnetic layer and whose magnetization direction ischangeable by an external magnetic field, and an intermediate layerwhich is provided between the second ferromagnetic layer and the thirdferromagnetic layer and which transmits a change of magnetizationdirection of the third ferromagnetic layer to the second ferromagneticlayer.
 10. The magneto-resistance effect element according to claim 8,wherein an aspect ratio of a plane shape of the magnetization free layeris within a range from 1 to 2 in any section parallel to the film facethereof.
 11. The magneto-resistance effect element according to claim 8,further comprising an anti-ferromagnetic layer formed on an oppositeside of the first ferromagnetic layer from the tunnel barrier layer. 12.The magneto-resistance effect element according to claim 8, wherein atleast one of the first ferromagnetic layer and the magnetization freelayer is a stacked film where a ferromagnetic film and a non-magneticfilm are stacked alternatively.
 13. The magneto-resistance effectelement according to claim 9, wherein the intermediate layer is asingle-layered ferromagnetic film or a stacked film where aferromagnetic film and a non-magnetic film are stacked alternatively,and anti-ferromagnetic exchange coupling or ferromagnetic exchangecoupling exists, via the non-magnetic film, between the adjacentferromagnetic films of the stacked film.
 14. The magneto-resistanceeffect element according to claim 9, wherein the second ferromagneticlayer and the intermediate layer have the same film face shape, and thethird ferromagnetic layer magnetically contact with the intermediatelayer.
 15. The magneto-resistance effect element according to claim 9,wherein the intermediate layer has the same film face shape as the thirdferromagnetic layer and is a non-magnetic metal layer.
 16. A magneticmemory comprising a first wiring, a second wiring crossing the firstwiring and a magneto-resistance effect element according to claim 1,which is provided in a crossing region of the first and second wirings,wherein the second and third ferromagnetic layers of themagneto-resistance effect element constitute a storage layer whosemagnetization direction is changeable according to a magnetic fieldgenerated by causing a current to flow in at least one wiring of thefirst and second wirings, and the third ferromagnetic layer is providedadjacent to the one wiring generating the magnetic field.
 17. Themagnetic memory according to claim 16, wherein a part of a periphery ofthe one wiring generating the magnetic field is covered with the thirdferromagnetic layer.
 18. The magnetic memory according to claim 16,wherein a yoke is provided on an opposite face of the one wiring, towhich the third ferromagnetic layer is provided adjacent, from the thirdferromagnetic layer.
 19. The magnetic memory according to claim 16,further comprising a MOS transistor or a diode for reading storageinformation in the magneto-resistance effect element.
 20. A magneticmemory comprising a first wiring, a second wiring crossing the firstwiring and a magneto-resistance effect element according to claim 8,which is provided in a crossing region of the first and second wirings,wherein the magnetization free layer of the magneto-resistance effectelement constitutes a storage layer whose magnetization direction ischangeable according to a magnetic field generated by causing a currentto flow in at least one wiring of the first and second wirings, and themagnetization free layer is provided adjacent to the one wiringgenerating the magnetic field.
 21. The magnetic memory according toclaim 20, wherein the magnetization free layer comprises a secondferromagnetic layer, a third ferromagnetic layer which is formed on anopposite side of the second ferromagnetic layer from the tunnel barrierlayer and has a film face having an area larger than that of the secondferromagnetic layer and whose magnetization direction is changeable byan external magnetic field, and an intermediate layer which is providedbetween the second ferromagnetic layer and the third ferromagnetic layerand which transmits a change of magnetization direction of the thirdferromagnetic layer to the second ferromagnetic layer, and the thirdferromagnetic layer is provided adjacent to the one wiring generatingthe magnetic field.
 22. The magnetic memory according to claim 21,wherein a part of a periphery of the one wiring generating the magneticfield is covered with the third ferromagnetic layer.
 23. The magneticmemory according to claim 21, wherein a yoke is provided on an oppositeface of the one wiring, to which the third ferromagnetic layer isprovided adjacent, from the third ferromagnetic layer.
 24. The magneticmemory according to claim 20, further comprising a MOS transistor or adiode for reading storage information in the magneto-resistance effectelement.
 25. A magnetic head comprising a magneto-resistance effectelement according to claim 1 as a magnetic reproducing element.
 26. Amagnetic head comprising a magneto-resistance effect element accordingto claim 8 as a magnetic reproducing element.